Combustion Engines with pre-combustion chambers are known from various prior art patents and other publications, such as AT 196669 E; AU 4634597A; AU 725961B; BR 9712894 A; CA 2271016 A1; CA 2271016 A; CH 691401 A; DE 69703215 T2; EP 937196 B1.
However, the known pre-combustion chamber has not been successfully commercialized. Many experiments have shown, that the pre-combustion chamber causes an increase of the efficiency of the combustion engines. This is only possible up to a rotary frequency of the shaft up to about 3000 min−1. Conventional pre-combustion chambers operated at higher frequencies cause a considerable decrease of the efficiency and a poor quality of the exhaust gases. The reason for this bad performance is the transport of the burnt fuel from the pre-combustion chamber to the main combustion chamber through a narrow passage requiring a time interval of more than 20 ms.
Schapiro-Engines are known with a different design of a rotational piston engine. This new kind of engine may operate with a considerably different rotational speed of the rotational piston and the shaft. Depending on the design of the engine the piston of such engines may, for example, rotate three to seven times slower than the shaft. Accordingly, the admissible time for transport of the gases combusted in the pre-combustion chamber into the primary combustion chamber is three to seven times longer in such engines.
Therefore, the critical limit for the rotational frequency of the shaft of a rotational piston engine with a pre-combustion chamber may be in the order of 9000 to 20000 min−1.